The Centre on Thursday told the Supreme Court that the Italian marines who killed two Indian fishermen in February 2012, purportedly mistaking them for pirates, did not enjoy any diplomatic immunity and are liable to be prosecuted here under Indian penal laws.

Appearing before a bench of justices Altamas Kabir and J. Chelameshwar, Additional Solicitor General Gourab Banerjee said the two armed marines do not enjoy any diplomatic immunity unlike other diplomats and embassy staffers.

"You (marines) have killed an Indian citizen on an Indian ship. We want to protect our citizens on our ships. As a matter of fact of law, armed personnel are not given any protection for their criminal action.''

"The immunity given to diplomatic or embassy staff is on a different footing. These gentlemen are not covered by any immunity. You (marines) are claiming immunity from criminal jurisdiction which we do not accept," Banerjee argued before the bench during the day-long hearing.

Responding to queries from the bench, Banerjee told it that India is not bound by the United Nations Convention on Jurisdictional Immunities of States and Their Property, 2004 as the convention has not come into force so far and India has not notified it.

He told the bench that the convention to become effective has to be signed by at least 30 member states, but as only 13 countries have signed it, it is not binding.

The court was hearing a petition filed by the Italian government and its two marines, challenging the May 29 order of the Kerala High Court, which had held that the duo - Chief Sargent Massimiliano Lattore and Sargent Salvatore Girone were liable to be tried by an Indian court.

Meanwhile, the Kerala government has also accused Italy of influencing witnesses to get acquittal of the marines.

"It is submitted that the attempts on the part of Republic of Italy to seek various disclaimers and even to compel the boat owner to enable an acquittal constitute direct interference in the administration of the criminal justice system," the Kerala government said.

Kerala complained that the Italian government on the one hand was trying to claim sovereign immunity but was attempting to reach a compromise with the families of the two fishermen through monetary allurements and was also trying to minimise the importance of the state government.

"It is stated that such a stand is completely inconsistent with the conduct of the petitioner as stated above. If the petitioner (Italy) believed that this was a matter between two nations, there was no occasion for the petitioner to have entered into an agreement with the victims.''

"It is extraordinary that the petitioner claims that it has offered humanitarian aid on terms and conditions without even alerting the Government of India or the state of Kerala that it was proceeding with such agreements.''

"Doramma (slain fisherman's wife) is a fisher woman who has studied up to SSLC (secondary school leaving certificate). It is impossible to believe that she signed an agreement with the Republic of Italy after having understood all those complex causes," said the Kerala government.

Asserting that the law and order is a state subject, the Kerala government said the conduct of the Italian government is not in conformity with either principles of international law or the principles of mutuality and respect accorded to other sovereign States.